Modification of colloidal metals and metal sulfides to reduce action as a nucleus for physical development



Sept. 14, 1965 A. H. HERZ 3,206,310 MODIFICATION OF COLLOIDAL METALS AND METAL SULFIDES TO REDUCE ACTION AS A NUGLEUS FOR PHYSICAL DEVELOPMENT Filed Aug. 25. 1961 BLUE SENSITIVE EMULSION 4 YELLOW FILTER IIVTERLAYER CONMW- m IIVG MOD/F/ED COLLOID/1L SILVER 1; GREEN SENSITIVE EMULS/O/V Fig. 2

BLUE SENSITIVE LAYER con/m/w/va MODIFIED COLLO/DAL s/LI/ER i GREEN SENSITIVE EMULS/O/V RED SENSITIVE EMULSION ARTHUR H l-lERZ INVENTOR.

BY XMAJJ 47' TOR/VEYS United States Patent 3,206,310 MODIFICATION OF COLLOIDAL METALS AND METAL SULFIDES TO REDUCE ACTION AS A NUCLEUS FOR PHYSICAL DEVELOPMENT Arthur H. Herz, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Filed Aug. 25, 1961,-Ser. No. 133,954 14 Claims. (Cl. 96-6'7) This invention relates to photography and particularly to a process of treating colloidal metals and colloidal metal sulfides to reduce action as physical development nuclei. Still more particularly this invention relates to the use of such modified metals and metal sulfides in photographic light-sensitive elements.

Colloidal metals and colloidal metal sulfides have a number of uses in photography. For example, colloidal silver is often used as the light filtering material in the yellow filter-interlayer between sensitive emulsion layers in certain multilayer color-forming photographic materials. One difiiculty encountered in photographic materials of this type, particularly where color-reversal processing is employed, is the formation of silver fog during silver development due to the colloidal silver acting as a nucleus for the physical development of silver ions from adjacent sensitive silver halide emulsions. This not only results in unwanted fog background but loss of silver as well from adjacent emulsion layers causing diminished color densities in the final product.

Another use made in photography of colloidal metals and colloidal metal sulfides has been described in my copending A. H. Herz, US. application, Serial No. 23,043,

filed April 18, 1960, now Patent No. 3,082,647 in which improved speed and contrast is obtained in photographic emulsions by employing the combination of a colloidal metal or colloidal metal sulfide with an alkylene oxide polymer. It is apparent that where colloidal materials such as these are incorporated directly into sensitive emulsion layers without the benefit of this invention, they will function as physical development nuclei with consequent deleterious effects.

Accordingly, it is an object of the present invention to provide a process formodifying the propensity of certain colloidal metals and colloidal metal sulfides to act as physical development nuclei. Another object is to provide novel photographic elements containing the modified colloidal metal and colloidal metal sulfides of the invention. A further object is to provide a process for preparing the novel photographic elements of the invention. Still other objects will become apparent from a reading of the specification and appended claims.

These objects are accomplished by treating a dispersion of the colloidal metal orcolloidal metal sulfides of the invention with an organic water-soluble compound which yields a thiol on hydrolysis. The thiol-yielding compounds which we have found to be especially useful for this purpose include alkyl-substituted quaternary salts selected from the class comprising sulfur and seleniumcontaining heterocyclic amines. Typical quaternary salts of thiazole and selenazole bases suitably employed in the invention can be represented by the following two general formulas:

wherein P and P each represents a member selected from the group consisting of sulfur or selenium, Z and Z each represents an organic group selected from the group consisting of vinylene, ethylene, phenylene, and naphthalene, Y represents an alkyl group (e.g., methyl, ethyl, propyl, hexyl, etc., especially alkyl groups containing from 1 to about 6 carbon atoms), a substituted alkyl group (e.g., methoxy, ethoxy, dodecyl, methylcarbethoxyl, sulf-obutyl, 2-methyl benzothiozolyl, etc.), an aromatic group (e.g., phenyl, naphthyl, etc), or a substituted aromatic group (e.g., chlorophenyl, etc.), R and R each represents a member selected from the group consisting of a hydrogen atom, an alkyl group (e.g., methyl, ethyl, propyl, butyl, etc., especially alkyl groups containing from 1 to about 6 carbon atoms), an alkoxy group (e.g., methoxy, ethoxy, etc), an aromatic group (e.g., phenyl, naphthyl, etc.), a substituted aromatic group (e.g., chlorophenyl, etc), or an alkylmercapto group (e.g., methylmercapto, ethylmercapto, propylmerca-pto, etc.), X and X each represents an acid anion (e.g., p-toluenesulfonate, perchlorate, sulfamate, ethylsulfate, benzenesulfonate, acetate, thiocyanate, chloride, bromide, iodide,-etc.), and n represents an integer greater than 1.

The method of preparing most of the foregoing chemical compounds is described, for example,-in Brooker et al., US. Patent 2,l31,038,'Septem=ber 27, 1938; Allen'et al., US. Patent 2,694,716, November 16, 1954; Allen et al., US. Patent 2,500,110, March 7, 1950; Wilson,-U.S. Patent 2,425,774, August 19, 1947; and in Carroll et al., US. Patent 2,334,864, November 23, 1943.

Although it is not completely certain how the invention works, it is thought that the modifying compounds of the invention yield thiols on hydrolysis which are adsorbed onto the surface of the colloidal metals or colloidal metal sulfides. If this is the case, it is mostunexpected that the thiols adsorbed onto the nucleating surface can modify the physical development properties of such nuclei without adversely affecting the sensitivity of admixed or contiguous silver halide emulsion layers. In accordance with the invention, the modifying substances, i.e., thiols, must not affect materially the oxidizability of the nuclei and interfere with subsequent bleaching in conventional processing solutions, for example, in reversal color processing. Suitable modifying substances also must not degrade the optical filtering properties of the physical nuclei. Such substances also must not cause a diminution in sensitivity of adjacent emulsion layers and must not diffuse from the particular layer in which they are incorporated.

Useful in the present invention as thiol-yielding compounds also are the derivatives of thiuroniums'and thi azolines such as thosedescribed in US. Patents 2,461,987, February 15, 1949; 2,514,650, July 11, 1950; and 2,131,- 038, September 27, 1938.

Other useful thiol-yielding compounds comprise certain thiol adducts, such as the thiol adducts of chalcone or azomethine compounds, such as p-acetamidothiophenol chalcone adduct, o-aminothiophenol chalcone adduct, mercapto pivalic acid-chalcone adduct, and p-thiocresolbenzal aniline adduct, and certain Michael adducts having the general formula:

wherein R R and R can each represent an aliphatic group having from 1 to about 8 carbon atoms, an aryl group, a substituted aryl group, a substituted aliphatic group, or a heterocyclic group.

Typical examples include for example:

( 1) fi-Carboxymethylmercaptobenzalacetophenone,

(2) ,B-(Z-diethylaminoethyl)-mercapto-B-phenylpropiophenone hydrochloride,

(3) ,8- 2-morpholinoethyl -mercapto-B-phenylpropiophenone hydrochloride,

(4) B-Carboxymethylthio-fi-phenyl-p-hydroxypropiophenone,

(5 (2-hyd-roxy) ethylthio-p-phenylpropiophenone,

(6) fi-Carboxymethylthio-B-phenyl-p-methoxypropiophenone,

(7) ,8-(2-morpholino)ethylthiopropiophenone hydrochloride,

(8) 4-(2'-morpholino)ethylthio-3-butanone perchlorate.

In the practice of the present invention, a colloidal metal or colloidal metal sulfide for treatment is prepared in an aqueous solution to which at least one thiol-yielding compound of the invention is added under conditions which promotes hydrolysis and yields the adsorbable thiol compound. The conditions required to promote hydrolysis of the thiol-yielding compounds of the invention are well known in the art. Such conditions normally comprise an alkaline pH although with many of the thiazolium salts of the invention, as well as many others, hydrolysis can occur at a pH even below 6.3. In some cases, a pH as low as 5.5 may be employed without inhibiting the hydrolysis reaction required in the present invention. In any event, the dispersion of colloidal nucleating material obtained after treatment with a suitable thiol-yielding compound under conditions to promote hydrolysis of said compound, is suitable for use in photography. Suitable uses, for example, include incorporation directly in the light-sensitive emulsion layers of various photographic elements, in light-filtering interlayers, in multilayer photographic color-forming elements, etc.

In accordance with the present invention, the concentration of the thiol-yielding compounds of the invention can vary widely in relation to the amount of colloidal material present. Useful concentrations, however, were found to be in the range from about 0.01 gram to about 5.0 grams of thiol-yielding compound per gram of colloidal material. The preferred range of concentration was found to be from about 0.1 gram to about 4.0 grams of thiol-yielding compound to colloidal material. The optimum concentration of thiol-donor in a particular system will, of course, vary with the thiol-donor compound and the colloidal material employed as well as with the particular pH employed to bring about the required hydrolysis according to the invention. Certain of the thiol-donors of the present invention have been found to yield thiols on hydrolysis at a pH as low as 3.3. Normally, however, a hydrolyzing pH in the range from about 4.5 to about 8.5 is employed with optimum results being obtained in a pH range from about 5.8 to about 7.0.

Suitable colloidal metals and colloidal metal sulfides according to the invention can include the colloidal metals; silver, gold, platinum, palladium, and the colloidal metal sulfides of silver, zinc, lead, nickel, cadmium, and copper. Other useful colloidal metals include colloidal selenides and colloidal tellurides.

In one embodiment of the invention, a yellow-filter interlayer containing modified colloidal silver is prepared as follows. The colloidal silver is first prepared in a fine state of subdivision by any one of a number of known methods, for example, by the Carey-Lea dextrin'reduction method as described in Colloidal Elements by Weiser, John Wiley and Sons, New York, N.Y., 1933, page 119. The colloidal silver so prepared and contained as an aqueous dispersion, is slowly mixed with a suitable colloid, e.g., gelatin, to which a thiol-yielding compound of the invention is added and the pH of the mixture is adjusted to an appropriate pH to promote hydrolysis of the thiol-yielding compound. The manner in which the yellow-filter interlayer can be placed with reference to emulsion layers in a multilayer photographic element is shown by reference to the accompanying drawing. In the sectional view thereof in FIG. 1, a support 10 is coated with emulsion layers 11, 12, and 13, sensitive, respectively to the red, green, and blue regions of the spectrum, and interlayer 14 contains the colloidal silver modified according to the invention. In FIG. 2 of the accompanying drawing, a support 10 is coated with emulsion layers 11, 12, and 15, sensitive, respectively to the red, green, and blue regions of the spectrum wherein the outermost layer 15 contains colloidal silver modified according to the invention.

It will be apparent that photographic elements having one or more light-sensitive emulsion layers may also advantageously be employed according to the present invention.

This invention is primarily directed to photographic elements ordinarily employing gelatino-silver-halide developing-out emulsions, e.g., gelatino-silver-chloride, -chlorobromide, -chloroiodide, -chlorobromoiodide, -bromide and -bromiodide developing-out emulsions. While the results in the following examples were obtained using gelatino-silver-bromiodide emulsions, excellent results can also be obtained using other silver halide emulsions. These emulsions can be coated in the usual manner on any suitable support, e.g., glass, cellulose nitrate film, cellulose ester film, polyvinylacetyl resin film, paper or metal.

Photographic silver halide emulsions useful in my invention can also contain such addenda as chemical sensitizers, e.g., sulfur sensitizers (e.g., allyl thioc-arbamide, thiourea, allyl isothiocyanate, cystine, etc.), various gold compounds (e.g. potassium chloroaurate, auric trichloride, etc.) (see US. Patents 2,540,085; 2,597,856; and 2,597,915), various azaindene compounds (such as those disclosed in US. Patent 2,716,062), condensation products of alkylene oxides, such as those shown in US. Patent 2,716,062), condensation products of alkylene oxides, such as those shown in US. Patent 2,400,532, as well as the additives mentioned in Jones et al., US. Patent 2,937,089.

The advantages of my invention are particularly well demonstrated in reversal color photographic processes whereln the color-forming compounds, or couplers, are incorporated in the color developing baths. The advantages of my invention are also outstanding in reversal color processes where a color film containing couplers in the emulsion (or alternatively in the color developers) has been given a hardening treatment in a bath prior to development color or black and white, so that development can be performed at a higher temperature and in a shorter period of time. Such hardening prebaths generally contain an aldehyde hardener, such as formaldehyde or succinaldehyde.

The photographic silver halide emulsions useful in the process of our invention can be prepared according to known methods, such as those described in Hewitson and McClintock, US. Patent, 2,618,556, issued November 18, 1952, for example. Of course, emulsions prepared by other methods can be used to equal advantage in this invention. These emulsions can be chemically sensitized or not, as mentioned above. Additional chemical sensitizers useful in this invention comprise those disclosed in US. Patent 2,886,437, issued May 12, 1959, in the name of D. E. Piper.

Emulsions of the present invention can contain alkylene oxide polymers, such as those used to sensitize photographic emulsions, such as polymers derived from alkylene oxides composed of from 2 to 4 carbon atoms, e.g., ethylene oxide, propylene oxide and butylene oxide. The preparation of polymers from these compounds is described in Ellis, The Chemistry of Synthetic Resins (1935), pages 990 to 994. The compounds embodying the invention are also referred to sometimes as polyalkylene glycols and their use as sensitizers for silver halide emulsions is described in U.S. Patents 2,423,549 and 2,441,389.

Various derivatives of alkylene oxides can also be used in accordance with this invention, e.g., condensation products of alkylene oxide with organic compounds containing an active hydrogen atom. Examples of active hydrogen organic compounds, i.e., compounds in which a hydrogen atom may be replaced by reaction of the compound with metallic sodium, methylmagnesium iodide, etc., include alcohols, amines, mer-captans, acids, amides, hydrocarbons, such as acetylene, and compounds having the active hydrogen in a methylene group, such as dibenzoylmethane. More specifically, we may employ condensation products of alkylene oxide with glycols, such as those having from 8 to 18 carbon atoms as described ,in U.S. Patent 2,240,472. and .British Patent 443,559 as well as condensation products of alkylene oxides with aliphatic alcohols, condensation products of alkyleneoxides with aliphatic acids, e,g., lauric acid and glycine, condensation products of alkylene oxides with aliphatic amines or amides, e.g., glycine and lauryl amide, and condensation products of alkylene oxides with phenols, e.g., phenol.

The preparation of these condensation products is described in U.S. Patent 1,970,578. Condensation products of alkylene oxides with hexitol ring dehydration 'productsas described in'U.'S. Patent 2,400,532 can also .ene oxide with organic compounds having an active hydrogen and with ethylene oxide polymers having a molecular weight of 100 to 3500 orwmore.

T-he'emulsions can also be optically sensitized with cyanine and merocyanine dyes, such as those described in Brooker, U.S. Patents 1,846,301, issued February 23, 1932; 1,846,302, issued February. 23, 1932; and 1,942,854, issued January 9, 1934; White, U.S. Patent 1,990,507, issued February 12, 1935; Brooker and White, U.S. Patents 2,112,140, issued March 22, 1938; 2,165,338, issued July 11, 1939; 2,493,747, issued January 10, 1950; and 2,739,964, issued March 27, 1956; Brooker and Keyes, U.S. Patent 2,493,748, issued January 10, 1950; Sprague, U.S. Patents 2,503,776, issued 'April 11, 1950; and 2,519,001, issued August 15, 1960; Heseltine and Brooker U.S. Patent 2,666,761, issued January 19, 1954; Heseltine, U.S. Patent 2,734,900, issued February 14, 1956; VanLare, U.S. Patent 2,739,149, issued March 20, 1956; and Kodak Limited British Patent 450,95 8, accepted July 15, 1936.

When employing optically sensitized emulsions, the optical sensitizing dyes are advantageously employed in about their usual optimum concentration although concentrations above or below the optimum concentration can be employed.

In preparing the color-forming elements of the present invention, couplers, which are useful in the photographic silver halide emulsion layers, have been described in a number of U.S. and foreign patents, for example, in U.S. Patents 2,956,876, October 18, 1960; 2,640,776, June 2, -1953; 2,407,210, September 3, 1946; 2,474,293, June 28,

1949; and 2,423,730, July 8, 1947.

Any of the conventional color-forming developing agents, which have been previously described in the prior art, can be used in the invention. The color-forming developers,which can be especially useful in this invention, include aromatic primary amines containing an amino (substituted or not) or hydroxyl substituent. Typical of such color-forming developers are the sulfonamido substituted p-phenylenediamines disclosed in Weissberger, U.S. Patent 2,548,574, issued April 10, 1951, the substituted p-phenylenediamines disclosed in Weissberger et al. in U.S. Patent 2,566,271, issued August 28, 1951.

The emulsions of the invention can also contain speedincreasing compounds of the quaternary ammonium type as described in U.S. Patents 2,271,623, February 3, 1942; 2,288,226, June 30, 1942; 2,334,864, November 23, 1943; or the thiopolymers as described in Graham et al. U.S. application Serial No. 779,839, filed December 12, 1958, now Patent No. 3,046,129; and Dann et al. U.S. applica tion Serial No. 779,874, filed December 12, 1958, now Patent No. 3,046,134.

The emulsion may also be chemically sensitized with reducing agents such as stannous salts (Carroll, U.S. Patent 2,487,850), polyamines such as diethylene triamine (Lowe and Jones, U.S. Patent 2,518,698), polyamines such as spermine (Lowe and Allen, U.S. Patent 2,521,- 9 25), or 'bis w-aminoethyhsulfide and its water-soluble salts (Lowe and Jones, U.S. Patent 2,521,926).

The emulsions may also be stabilized with the mercury compounds of Allen, Byers and Murray, U.S. application Serial No. 319,611; Carroll and Murray, U.S. application Serial No. 319,612; and Leubner and Murray, U.S. application Serial No. 319,613, all filed November 8, 1952,

now US. Patents 2,728,663; 2,728,664 and 2,728,665, re-

hardeners for gelatin (e.g., formaldehyde, mucobromic acid, an acid compound as described in U.S. Patents 2,725,294 and 2,725,295, Nov-ember 29, 1955, a cyclic 1,2-diketone as described in Allen et a1. U.S. 2,725,305, November 29, 1955, and the like), and coating aids (e.g., saponin, a lauryl monoether of polyethylene glycol as described in Knox et al. U.S. Patent 2,831,766, April 22, 8, a salt of a sulfated and alkylated polyethylene glycol ether as described in Knox et al. U.S. 2,719,087, a water-soluble male'oprimarate as described in .Knox et al. U.S. 2,823,123, February 11, 1958, etc.). The dispersing agent for the silver halide can be gelatin or other hydrophilic material such as collodion, albumin, cellulose derivatives and synthetic resins.

These may also be used in emulsions intended for use in diffusion transfer processes which utilize the nude veloped silver halide in the nonimage areas of the negative to form a positive by dissolving the undeveloped silver halide and precipitating it on a receiving layer in close proximity to the original silver halide emulsion layer. Such processes are described in Rott, U.S. Patent 2,352,014, issued June 20, 1944, and Land, U.S. Patents 2,584,029, issued January 29, 1952; 2,698,236, issued 'December 28, 1954; and 2,543,181, issued February 27,

1951; and-Yack'el et al. U.S. patent application Serial No. 586,705, filed May 23, 1956, now U.S. Patent No. 3,020,- 155. They may also be used in color transfer processes which utilize the diifusion transfer of an imagewise distribution of developer, coupler or dye, from a light-sensitive layer to a second layer, while the two layers are in close, proximity to one another. Color processes of this type'are described in Land, U.S. Patents 2,559,643, issued July 10, 1951, and 2,698,798, issued January 4, 1955; Land and Rogers, Belgian Patents 554,933 and 554,934, granted August 12, 1957; International Polaroid, Belgian Patents 554,212, granted July 16, 1957, and 554,935, granted August 12, 1957; Yutzy, U.S. Patent 2,756,142,

granted July 24, 1956, and Whitmore and Mader, US. patent application Serial No. 734,141, filed May 9, 1958, now abandoned. They may also be used in emulsions intended for use in a monobath process such as described in Haist et al. US. Patent 2,875,048, issued February 24, 1959, and in web-type processes, such as the one described in Tregillus et al. US. patent application Serial No. 835, 473, filed August 24, 1959.

Where a reversal process is employed, the first developer, i.e., :Black-and-White Negative Developer is generally a rapid developer of the MQ type, i.e., a combina tion of hydroquinone and Elon developer (p-N-methylaminophenol). Other black-and-white developers, such as hydroquinone alone, pyrazolidone developers (e.g., 1-phenyl-3-pyrazolidone, 4,4 dimethyl-l-phenyl-S-pyrazolidone, etc.) can also be used.

The invention will now be further explained by reference to the following examples.

EXAMPLE 1 This example shows decreased silver fog in multilayer photographic elements after reversal color processing where modified yellow-filter-colloidal silver is employed in accordance with this invention.

To form a standard of comparison three preparations were made:

Sample 1.A control interlayer composition was prepared as follows: To a gelatin solution containing 1.0 gram of Carey-Lea silver, prepared by the dextrin-reduction method referred to herein, 0.01 molar potassium bromide was added to give a silver ion activity of about X10 ions per liter at 40 C. After further addition of gelatin and adjustment to pH 7.8, the dispersion was well mixed and ready for coating.

Sample 2.An interlayer composition was prepared as follows: To a gelatin solution containing 1.0 gram of Carey-Lea silver per liter at 40 C., there was added 0.01 molar of 3-(2-benzthiazolylmethyl) benzthiazolium ptoluene sulfonate to give a silver ion activity of about =5 10 ions per liter at 40 C. After further addition of gelatin and adjustment to pH 7.8, the dispersion was Well mixed and ready for coating.

Sample 3.An interlayer composition was prepared as follows: To a gelatin solution containing 1.0 gram of Carey-Lea silver there was added 0.01 molar methylbenzthiazolium'methosulfate to give a silver ion activity of about 5 1O- ions per liter at 40 C. The gelatin addition, pH adjustment and mixing was carried out the same as in Sample 2.

Each of the three preparations was used as the yellow filter interlayer in each of three separate multilayer films of the type described in Mannes et al. US. Patent 2,252,- 718, issued August 19, 1941. The films of the present example have silver bromiodide emulsion layers sensitized respectively to the blue, green, and red spectral regions, with the blue-sensitive layer being outermost, the colloidal silver filter interlayer being next, the green-sensitive emulsion layer being next, and the red-sensitive emulsion layer being adjacent to the acetate support.

Each film was given a sensitometric exposure of 4 second to light emitted by a SOD-watt tungsten lamp adjusted to a temperature of 3,000 K. in an intensity scale sensitometer, and further modulated by a 0.6 neutral density. Strips of each of these films were then developed for various times at 80 F. in developer solutions of the following compositions:

Water to 1.0 liter.

silver dispersion of the Carey-Lea Water to 1.0 liter.

The separate strips of film were then fixed for 5 minutes in a solution of grams of sodium thiosulfate and 20 grams of sodium bisulfite in 1 liter of water and dried. A chemical analysis for silver (fog) was then made in strips of each of the films. The results appear in the fol lowing table:

Table 3 Development Sample 1 Mg. Ag/ft. Sample 3 Sample 2 5 minutes in developer of Table 1 136 64 71 7 minutes in developer of Table 1 183 101 103 9 minutes in developer of Table 1 229 140 149 3 minutes in developer of Table 2 148 113 111 3.5 minutes in developer of Table 2 167 140 135 4.2 minutes in developer of Table 2 205 170 167 The results of this example show that coatings made from Samples 2 and 3, the coatings containing the modified colloidal silver in the yellow filter interlayer, gave lower values for silver content than did Sample 1, the control.

Separate strips of each of the three films were reversal processed according to the process described in Sease et al. US. Patent 2,319,369, issued May 18, 1943. The processed strips showed the photographic elements having in terlayers corresponding to Samples 2 and 3 had yellow and magento maximum densities much higher than did the Sample 1 control strips.

EXAMPLE 2 The following example illustrates a two-layer coating in which a spectrally nonsensitized photographic emulsion Was coated over a colloidal silver dispersion in gelatin.

A series of two-layer coatings was made on cellulose acetate film base, in which a negative speed gelatin-silver bromiodide emulsion prepared according to Hewitson and McClintock, US. Patent 2,618,556, issued November 18, 1952, was coated over a colloidal silver dispersion in gelatin.

The following were prepared:

(1) Colloidal silver dispersion A.An aqueous yellow type as previously described containing 3.3 grams gelatin and 0.162 gram silver per 10 grams dispersion was coated, at a pH of 6.3, on a cellulose acetate film base at 6.8 grams dispersion per square foot.

(2) Colloidal silver dispersion B.The same as colloidal dispersion A, except 0.018 gram N-benzyl benzothiazolium chloride was added per 100 grams of dispersion.

(3) Coating X .A fast, negative-type bromiodide emulsion containing 3.6 grams gelatin and 1.5 grams silver halide per 100 grams was coated at pH 6.3 over a layer of dispersion A at 7.2 grams per square foot.

(4) Coating X .San1e as X except the emulsion contained also 0.0018 gram N-benzyl.benzothiazolium.chloride per 100 grams of emulsion.

Coating X .Sarne as X except the emulsion contained also 0.006 gram N-benzyl benzothiazolium chloride per 100 grams of emulsion.

(6) Coating X .;.Same as X except the emulsion contained also 0.018 gram N-benzyl benzothiazolium chloride per 100 grams of emulsion.

(7) Coating X .--A fast, negative-type bromiodide emulsion containing 3.6 grams gelatinand' 1.5 grams of silver halide per 100 grams'was coated at pH 6.3 over a layer fo colloidal-silver dispersion B at 7.2 grams per square foot.

Each of the above strips employinga two-layer coating was exposed and processed in a photographic developer of Table 4 at 68 F. for the indicated time.

Cold water to 1.0 liter.

10 August 19, 1941, was prepared employing a colloidal silver yellow filter interlayer between the outermost bluesensitive layer and the green-sensitive layer. The redsensitive layer being coated adjacent the support.

lwo additional photographic elements were prepared ina similar manner except that the colloidal silver of the 'yellow filter-interlayer was modified according to the invention. The schedule occurs as follows:

Coating:

X ControlNonmodified colloidal lsilver. .X Colloidal silver treated with 3-(2-benzthiazolylmethyDbenZ- thiazolium p-toluene-sulfonate as in Sample 2 of Example 1.

X Colloidal silver treated with methyl benzthiazolium metho-suL fateas in Sample 3 of Example 1.

Each of the elements were then exposed to an original :multicolored scene and processed in identical manner as follows:

The photographic elements were developed for about 3 /2 minutes at 80 F., in a developer having the following composition:

. scribed in Mannes et al. U.S. Patent 2,252,718, issued -Theresults of the example are given in the table Quad'rofos "grams" 0.6 below. The speed values-in Table 5 are relative speeds Sodium sulfite do 12.0 'measuredat the exposure level required to produce a pN-methylaminophenol sulfate do '50 density of 0.3 above fog. Sodium hydroxide do 1.0

Table 5 4-minute development 6-minute development Coating number L Relative Fog Mg. Ag llt. Relative Fog Mg. Ag lft.

speed speed *No image.

In the separate coatings ofTable' 5 is shown the'effect Hydroquinone do 2.0 *on speed, fog and silver deposition in two-layer photo- Sodium sulfite do 60 graphic strips .where a -.layer :of gelatino silver-halide Sodium carbonate do 35.0 emulsi-on-is coated over a gelatin layer containing 001- Potassium iodide (0.1% solution) ml 10.0 'loidal' silver modified accordingto. the present inven- Sodium bromide grams 3.0 tion. Suitable controls are embodied in .the trial to show Sodium thiocyanate do 1.75 relative effects obtained where the inventionisemployed. -Water to 1.0 liter.

From the table it is apparent that treatment o f -sodium tetraphosphate (or hexametaphosphate). loidal silver with a thi-ol-donor dimimshes deposition of 50 Th h t a 1 t th h d silver on the nuclei during development, and also results t O E g en spray was 6 W1 d in increased speed in adjacent silver emulsion halide i i a g 3i glveg anfifposure to Te layers. Reference is made to coatings X vs. X i i 3 1 5 6 Sewn 1 e 35 g The results .in the table also show that upon addition of fi W f en Y ope m a cyan eve Opelavmg e the thiol-donor to the emulsion instead of to the silver O owmg Ormu dispersion, that little diminution of physical development Quadrofo's 1 grams 0.7 on the nuclei results without a large sacrifice in emulsion Sodium bromide 1do 2.50 speed. The diiference'in behavior of the thiol-donor com- Potassium iodide (0.1% solution) ml 5 .0 pound, depending on whether it is incorporated in the Sodium sulfite grams 10.0 emulsion or employed to modify the colloidal silver ac- Sodium sulfate do 20.0 cording to the invention, is particularly apparent from a Sodium hydroxide do 3.30 comparison of coatingsX and X 111 each case 1.3 mg. 6'-nitrobenzimidazole (1% solution) 1% sodium N-benzyl benzthiazolium chloride was contained per hydroxide ml 5.0 square foot of coating. In the coating where the thiolp-N-benzylaminophenol "grams" 0.70 :donorwasadded-tothe emulsion under the given con- 0 Coupler do 1.50

ditions, desensitization was so strong that no image de- -4-amino-N,N-diethyl-3-methylanilinehydroveloped. chloride do 2.60

0 EXAMPLE 3 Water to 1.0 liter. A multilayer photographs element of the type defifi i b eiii];iiiii g l l ii iiglethyl) l-hydroxynaphthamide.

As hydrochloride.

The photographic element was then washed for about /2 minute With Water and exposed to blue light of 300 ft. candle seconds intensity and developed in a yellow color developer containing a phenylenediamine color-developing agent, such as 4-amino-N,N-diethylaniline hydrochloride and a yellow coupler, such as coupler N0. 47 from column 4 of US. Patent 2,956,876. The photographic element was then washed and fogged chemically by treat ment with a sodium borohydride solution, as described in Henn et al. US. application Serial No. 699,478, filed November 29, 1957, now Patent No. 2,984,567. The photographic element was then developed in a magenta 7 color developer containing a color developing agent, such as 4-aminoN,N-diethyl-3-methylaniline hydrochloride and a magenta coupler, such as coupler No. 30 in column 4 of US. Patent 2,956,876.

The elements were then bleached and fixed in a well known manner, for example, as described in Sease et al. US. Patent 2,319,369, issued May 18, 1943. Thereafter, the elements were washed and dried; and the results shown in the following table were obtained. The reversal maximum densities were obtained in a well known manner, i.e., the yellow-dye image using a blue light, the magentadye image with a green light and the cyan-dye image with a red light. The silver analysis was by a chemical method calibrated to measure metallic silver in mg./ft. at a given emulsion thickness.

Reversal Dmnx Coating Number Yellow Magenta. Cyan SILVER DEVELOPED IN EACH DEVELOPER OF THE PROCESS (in. mg./ft.

Coating Number Developer vi yz Xya Total 441 440 446 Raw stock analysis 441 441 443 'EXAMPLE 4 A chemically sensitized, negative-type bromiodide emulsion containing zinc sulfide nuclei as shown below in grams per mole of silver was coated on a clear acetate support and dried. The coated emulsion was exposed in an Eastman l-B sensi-tometer and then processed for 6 minutes in a developer having the composition given in Table 4 of Example 2. The results appear below:

The results show that colloidal zinc sulfide when modified by treatment with N-benzyl benzthiaz-olium chloride has no appreciable efiect on speed but diminishes strongly the amount of silver deposited on the sulfide nuclei by physical development. A large deposition of silver on the zinc sulfide nuclei has occurred in the controls, i.e., nontreated zinc sulfide samples, results in a higher optical density accompanied by a high residual silver content after fixing.

Similar results can be obtained using other colloidal metals and colloidal metal sulfides as outlined elsewhere in this specification.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be etfected within the scope and spirit of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. A method of reducing physical development activity of colloidal particles in a photographic silver halide element that comprises a film layer in which are dispersed colloidal particles of a material selected from the group consisting of noble metals and sulfides of silver, zinc, lead, nickel, cadmium and copper, said method comprising the step, prior to coating said layer, of mixing colloidal particles of said material and a thiol-yielding compound into the aqueous film-coating solution to be used in coating of said layer, with the pH of said solution high enough to promote hydrolysis of said thiol-yielding compound in the aqueous solution; said thiol-yielding compound being one selected from compounds having the formulas:

P 20-3 N--X i and N(GHZ)DN 21 1';

wherein:

P is selected from the group consisting of sulfur and selenium,

Z is selected from the group consisting of vinylene, ethylene, phenylene and naphthalene,

Y is selected from the group consisting of alkyl and alkoxy radicals having from 1 to about 6 carbon atoms, aryl, and substituted aryl,

13 R is selected from the group consisting of hydrogen, alkyl and alkoxy radicals having 1 to about 6 carbon atoms, and alkylmercapto having 1 to 4 carbon atoms, X is an anion and n is an integer greater than 1.

2. The process according to claim 1 wherein said thiolyielding compound has the general formula:

wherein Y represents an alkyl group having from 1 to about 6 carbon atoms, and X represents an acid anion.

3. The process according to claim 1 wherein said thiolyielding compound has the general formula:

C-CHa [X 4.

wherein X represents an acid anion and Y represents an alkyl group having 1 to 6 carbon atoms.

4. The process according to claim 1 wherein said thiolyielding compound has the general formula:

7. The process of claim 1 wherein said thiol-yielding compound is N-benzyl benzthiazolium chloride.

8. The process of claim 1 wherein said colloidal particles are silver and said thiol-yielding compound is 3-(2- benzthiazolylmethyl) benzthiazolium p-toluene sulfate.

9. The process of claim 1 wherein said colloidal particles are silver and said thiol-yielding compound is methylbenzthiazolium methosulfate.

10. The process of claim 1 wherein said colloidal particles are zinc sulfide and said thiol-yielding compound is N-benzyl benzthiazolium chloride.

11. A photographic element comprising a support with at least one silver halide emulsion film layer coated thereon and having at least one film layer coated thereon in which are dispersed colloidal particles of material selected from the group consisting of noble metals and sulfides of silver, zinc, lead, nickel, cadmium and copper whose physical development activity has been reduced prior to coating by the method defined in claim 1.

12. A photographic element comprising a support having coated thereon a plurality of film layers comprising at least one photosensitive silver halide layer and a lightinsensitive filter layer, the filter layer having dispersed therein colloidal particles of silver whose physical development activity has been reduced by the method defined in claim 1.

13. A photographic element comprising a support having coated thereon a plurality of film layers comprising at least one photosensitive silver halide film layer in which are dispersed colloidal particles of zinc sulfide whose physical development activity has been reduced by the method of claim 1.

14. A photographic element of claim 11 wherein said colloidal material is colloidal silver.

References Cited by the Examiner UNITED STATES PATENTS 2,336,327 12/ 43 Weissberger 96-74 2,597,915 5/52 Yutzy et al. 96-l09 2,614,925 10/52 Carroll et a1 96-66 2,735,764 2/56 Allen et al. 96-56 X 3,113,864 12/63 Yager et al. 96-56 X NORMAN G. TORCHIN, Primary Examiner. 

1. A METHOD OF REDUCING PHYSICAL DEVELOPMENT ACTIVITY OF COLLOIDAL PARTICLES IN A PHOTOGRAPHIC SILVER HALIDE ELEMENT THAT COMPRISES A FILM LAYER IN WHICH ARE DISPERSED COLLOIDAL PARTICLES OF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF NOBLE METALS AND SULFIDES OF SILVER, ZINC, LEAD, NICKEL, CADMIUM AND COPPER, SAID METHOD COMPRISING STEP, PRIOR TO COATING SAID LAYER, OF MIXING COLLOIDAL PARTICLES OF SAID MATERIAL AND A THIO-YIELDING COMPOUND INTO THE AQUEOUS FILM-COATING SOLUTION TO BE USED IN COATING OF SAID LAYER, WITH THE PH OF SAID SOLUTION HIGH ENOUGH TO PROMOTE HYDROLYSIS OF SAID THIO-YIELDING COMPOUND IN THE AQUEOUS SOLUTION; SAID THIO-YIELDING COMPOUND BEING ONE SELECTED FROM COMPOUNDS HAVING THE FORMULAS: R-C<(-P-Z-N(-X)(-Y)=) AND R-C<(-P-Z-N(-X)(-(CH2)N-N(-X)< (=C(-R)-P-Z-)=) WHEREIN:
 11. A PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT WITH AT LEAST ONE SILVER HALIDE EMULSION FILM LAYER COATED THEREON AND HAVING AT LEAST ONE FILM LAYER COATED THEREON IN WHICH ARE DISPERSED COLLOIDAL PARTICLES OF MATERIAL SELECTED FROM THE GROUP CONSISTING OF NOBLE METALS AND SULFIDES OF SILVER, ZINC, LEAD, NICKEL, CADMIUM AND COPPER WHOSE PHYSICAL DEVELOPMENT ACTIVITY HAS BEEN REDUCED PRIOR TO COATING BY THE METHOD DEFINED IN CLAIM
 1. 